Bacterial Pathogenesis, Molecular Basis of
Representative virulence factors/mechanisms and their functions.
Enhanced ability of motile organisms to
disseminate to other tissues.
Inhibition of cell lysis by inhibiting the
formation of the activated
Destruction of tissue for dissemination;
provision of nutrients.
Destruction of complement, antibodies,
and other host cell defense proteins.
Variation of surface proteins to evade
host antibody response.
Killing of host immune response cells
(phagocytes, PMNs, etc). Destruction
of tissue to enhance nutrient
availability and possible
dissemination to other sites.
Pili or Fmbriae
Adhesion to host cells and mucosal
Adhesion to cells and mucosal tissue.
surface proteins that
Acquisition of iron from host sources.
Decrease activation of complement.
Evasion of host immune response.
strategies and mechanisms to cause in-
fection and disease. While not applicable
in every case, almost all pathogens must
successfully complete a series of common
steps in order to ﬂourish. First, a pathogen
must gain entry into the host. Second, the
pathogen must be able to establish itself
(colonize) and adhere to host cell tissues.
Third, the pathogen must be able to sur-
vive within the host. Fourth, the pathogen
must be able to cause cell or tissue damage.
Lastly, the pathogen must be able to dis-
seminate from the host in order to infect a
The process may appear to be simple,
but one must remember that pathogens
face considerable challenges in attempting
to complete the steps outlined above.
Almost immediately these organisms face
the task of outcompeting the normal